U.S. patent application number 11/400551 was filed with the patent office on 2007-10-11 for post hole digger.
This patent application is currently assigned to Ames True Temper, Inc.. Invention is credited to Barry R. Albert, Jeffrey M. Norton.
Application Number | 20070236026 11/400551 |
Document ID | / |
Family ID | 38574458 |
Filed Date | 2007-10-11 |
United States Patent
Application |
20070236026 |
Kind Code |
A1 |
Norton; Jeffrey M. ; et
al. |
October 11, 2007 |
Post hole digger
Abstract
This invention provides a post hole digger having a first,
traverse pivot point, located on the medial portions of two handle
members, and a second, blade assembly pivot point located at the
medial point of the blade assemblies. Because the first pivot point
is a traverse pivot point, the handle members are only required to
travel through a limited range of motion. Additionally, the second,
blade assembly pivot point is preferably an offset pivot point.
Thus, because the second, blade assembly pivot point is disposed at
a medial point of the blade assemblies, the motion of the handle
members, which are coupled to the upper ends of the blade
assemblies, is reversed relative to the lower ends of the blade
members.
Inventors: |
Norton; Jeffrey M.;
(Lebanon, PA) ; Albert; Barry R.; (Dillsburg,
PA) |
Correspondence
Address: |
David C. Jenkins;Eckert Seamans Cherin & Mellott, LLC
44th Floor
600 Grant Street
Pittsburgh
PA
15219
US
|
Assignee: |
Ames True Temper, Inc.
Camp Hill
PA
|
Family ID: |
38574458 |
Appl. No.: |
11/400551 |
Filed: |
April 7, 2006 |
Current U.S.
Class: |
294/50.8 |
Current CPC
Class: |
E21B 11/005 20130101;
G02B 2006/1204 20130101; G02B 6/122 20130101 |
Class at
Publication: |
294/050.8 |
International
Class: |
A01B 1/00 20060101
A01B001/00 |
Claims
1. A post hole digger comprising: a first handle assembly having an
upper end, a medial portion, and a lower end; a second handle
assembly having an upper end, a medial portion, and a lower end;
said first handle assembly pivotally coupled to said second handle
assembly at a first, traverse pivot point, said first, traverse
pivot point disposed on said first handle assembly medial portion
and said second handle assembly medial portion; a blade assembly
having a first blade sub-assembly and a second blade sub-assembly;
said first blade sub-assembly pivotally coupled to said first
handle assembly, said first blade sub-assembly having an elongated
blade member having an upper end and a lower end; said second blade
sub-assembly pivotally coupled to said second handle assembly, said
second blade sub-assembly having an elongated blade member having
an upper end and a lower end; said first blade sub-assembly and
said second blade sub-assembly coupled together at a blade assembly
pivot point, said blade assembly pivot point disposed on said first
blade sub-assembly blade member upper end and said second blade
sub-assembly blade member upper end; and a central longitudinal
axis extending through said traverse, first pivot point and said
blade assembly pivot point.
2. The post hole digger of claim 1 wherein: said first blade
sub-assembly includes an offset tab extending from said first blade
sub-assembly blade member upper end; said second blade sub-assembly
includes an offset tab extending from said second blade
sub-assembly blade member upper end; and wherein said blade
assembly pivot point is an offset pivot point, the axis of said
blade assembly pivot point passing through said first blade
sub-assembly offset tab and said second blade sub-assembly offset
tab.
3. The post hole digger of claim 1 wherein: said first handle
assembly and said second handle assembly are structured to pivot
relative to each other between a first position, wherein said first
handle assembly upper end and said second handle assembly upper end
adjacent to each other and a second position wherein said first
handle assembly upper end and said second handle assembly upper end
are generally spaced from each other; and said first blade
sub-assembly and said second blade sub-assembly being structured to
pivot relative to each other between a first, open position and a
second, closed position, and wherein when said first handle
assembly and said second handle assembly are in said first
position, said first blade sub-assembly and said second blade
sub-assembly are in said first, open position, and, when said first
handle assembly and said second handle assembly are in said second
position, said first blade sub-assembly and said second blade
sub-assembly are in said second, closed position.
4. The post hole digger of claim 3 wherein said first handle
assembly and said second handle assembly travel between about 6.5
degrees and 10.5 degrees relative to said central longitudinal axis
when moved between said first position and said second
position.
5. The post hole digger of claim 4 wherein said first handle
assembly and said second handle assembly travel about 8.5 degrees
relative to said central longitudinal axis when moved between said
first position and said second position.
6. The post hole digger of claim 4 wherein: said first blade
sub-assembly blade member is elongated and has a longitudinal axis:
said second blade sub-assembly blade member is elongated and has a
longitudinal axis; said first blade sub-assembly includes an
elongated blade base having a longitudinal axis, said first blade
sub-assembly blade base longitudinal axis being angled relative to
said first blade sub-assembly blade member longitudinal axis; and
said second blade sub-assembly includes an elongated blade base
having a longitudinal axis, said second blade sub-assembly blade
base longitudinal axis being angled relative to said second blade
sub-assembly blade member longitudinal axis.
7. The post hole digger of claim 6 wherein: said first handle
assembly includes an elongated handle member, said first handle
assembly handle member having an extended, upper portion with a
longitudinal axis, a medial portion having a longitudinal axis, and
a lower portion having a longitudinal axis; said second handle
assembly includes an elongated handle member, said second handle
assembly handle member having an extended, upper portion with a
longitudinal axis, a medial portion having a longitudinal axis, and
a lower portion having a longitudinal axis; said first handle
assembly handle member upper portion longitudinal axis being angled
between about 20 to 24 degrees relative to said first handle
assembly handle member medial portion longitudinal axis; said first
handle assembly handle member lower portion longitudinal axis being
angled in a direction generally opposite of said first handle
assembly upper portion longitudinal axis between about 26 to 30
degrees relative to said first handle assembly handle member medial
portion longitudinal axis; said second handle assembly handle
member upper portion longitudinal axis being angled between about
20 to 24 degrees relative to said second handle assembly handle
member medial portion longitudinal axis; and said second handle
assembly handle member lower portion longitudinal axis being angled
in a direction generally opposite of said second handle assembly
handle member upper portion longitudinal axis between about 26 to
30 degrees relative to said second handle assembly handle member
medial portion longitudinal axis.
8. The post hole digger of claim 6 wherein: said first handle
assembly lower end is between about 6 and 10 inches from said
traverse, first pivot point; said second handle assembly lower end
is between about 6 and 10 inches from said traverse, first pivot
point; said second, offset pivot point is disposed between about 10
and 14 inches from said traverse, first pivot point; said first
blade sub-assembly offset tab has a length of between about 4.5 and
5.5; said second blade sub-assembly offset tab has a length of
between about 4.5 and 5.5; said first blade sub-assembly blade
portion having a length of between about 9.5 and 11.5; and said
second blade sub-assembly blade member having a length of between
about 9.5 and 11.5.
9. The post hole digger of claim 6 wherein: said first blade
sub-assembly base portion longitudinal axis is angled between about
18 and 22 degrees relative to said first blade sub-assembly base
portion longitudinal axis; and said second blade sub-assembly base
portion longitudinal axis is angled between about 18 and 22 degrees
relative to said second blade sub-assembly blade member
longitudinal axis.
10. The post hole digger of claim 6 wherein: said first blade
sub-assembly blade portion travels between about 12 degrees and 18
degrees relative to said central longitudinal axis as said first
blade sub-assembly moves between said first, open position and said
second, closed position; and said second blade sub-assembly blade
portion travels between about 12 degrees and 18 degrees relative to
said central longitudinal axis as said second blade sub-assembly
moves between said first, open position and said second, closed
position.
11. The post hole digger of claim 7 wherein: said first handle
assembly handle member upper portion longitudinal axis is angled
about 22.5 degrees relative to said first handle assembly handle
member medial portion longitudinal axis; said first handle assembly
handle member lower portion longitudinal axis is angled in a
direction generally opposite of said first handle assembly handle
member upper portion longitudinal axis about 28 degrees relative to
said first handle assembly handle member medial portion
longitudinal axis; said second handle assembly handle member upper
portion longitudinal axis is angled about 22.5 degrees relative to
said second handle assembly handle member medial portion
longitudinal axis; and said second handle assembly handle member
lower portion longitudinal axis is angled in a direction generally
opposite of said second handle assembly handle member upper portion
longitudinal axis about 28 degrees relative to said second handle
assembly handle member medial portion longitudinal axis.
12. The post hole digger of claim 11 wherein: said first handle
assembly lower end is about 8.0 inches from said traverse, first
pivot point; said second handle assembly lower end is about 8.0
inches from said traverse, first pivot point; said second, offset
pivot point is disposed about 12.0 inches from said traverse, first
pivot point; said first blade sub-assembly offset tab has a length
of about 5.0; said second blade sub-assembly offset tab has a
length of about 5.0; said first blade sub-assembly blade member
having a length of about 10.5; and said second blade sub-assembly
blade member having a length of about 10.5.
13. The post hole digger of claim 11 wherein: said first blade
sub-assembly base portion longitudinal axis is angled about 20.3
degrees relative to said first blade sub-assembly blade portion
longitudinal axis; and said second blade sub-assembly base portion
longitudinal axis is angled about 20.3 degrees relative to said
second blade sub-assembly blade member longitudinal axis.
14. The post hole digger of claim 11 wherein: said first blade
sub-assembly blade member travels about 15 degrees relative to said
central longitudinal axis as said first blade sub-assembly moves
between said first, open position and said second, closed position;
and said second blade sub-assembly blade member travels about 15
degrees relative to said central longitudinal axis as said second
blade sub-assembly moves between said first, open position and said
second, closed position.
15. The post hole digger of claim 11 wherein: said first handle
assembly handle member lower portion and said first handle assembly
handle member medial portion being generally disposed in a first
lower plane; said first handle assembly handle member medial
portion has a lateral transition section, said first handle
assembly lateral transition section being offset from said first
lower plane; said first handle assembly handle member medial
portion lateral transition section disposed between said first
pivot point and said first handle assembly handle member upper
portion, whereby said first handle assembly handle member upper
portion is disposed in an upper plane; said second handle assembly
handle member lower portion and said second handle assembly handle
member medial portion being generally disposed in a second lower
plane; said second handle assembly handle member medial portion has
a lateral transition section, said second handle assembly lateral
transition section being offset from said second lower plane; said
second handle assembly handle member medial portion lateral
transition section disposed between said first pivot point and said
second handle assembly handle member upper portion, whereby said
second handle assembly handle member upper portion is disposed in
an upper plane; and wherein said first handle assembly handle
member upper portion and said second handle assembly handle member
upper portion are disposed in generally the same plane.
16. The post hole digger of claim 7 wherein: said first handle
assembly handle member lower portion and said first handle assembly
handle member medial portion being generally disposed in a first
lower plane; said first handle assembly handle member medial
portion has a lateral transition section, said first handle
assembly lateral transition section being offset from said first
lower plane; said first handle assembly handle member medial
portion lateral transition section disposed between said first
pivot point and said first handle assembly handle member upper
portion, whereby said first handle assembly handle member upper
portion is disposed in an upper plane; said second handle assembly
handle member lower portion and said second handle assembly handle
member medial portion being generally disposed in a second lower
plane; said second handle assembly handle member medial portion has
a lateral transition section, said second handle assembly lateral
transition section being offset from said second lower plane; said
second handle assembly handle member medial portion lateral
transition section disposed between said first pivot point and said
second handle assembly handle member upper portion, whereby said
second handle assembly handle member upper portion is disposed in
an upper plane; and wherein said first handle assembly handle
member upper portion and said second handle assembly handle member
upper portion are disposed in generally the same plane.
17. The post hole digger of claim 4 wherein: said first blade
sub-assembly blade portion travels between about 12 degrees and 18
degrees relative to said central longitudinal axis as said first
blade sub-assembly moves between said first, open position and said
second, closed position; and said second blade sub-assembly blade
portion travels between about 12 degrees and 18 degrees relative to
said central longitudinal axis as said second blade sub-assembly
moves between said first, open position and said second, closed
position.
18. The post hole digger of claim 17 wherein: said first blade
sub-assembly blade portion travels about 15 degrees relative to
said central longitudinal axis as said first blade sub-assembly
moves between said first, open position and said second, closed
position; and said second blade sub-assembly blade member travels
about 15 degrees relative to said central longitudinal axis as said
second blade sub-assembly moves between said first, open position
and said second, closed position.
19. The post hole digger of claim 3 wherein: said first handle
assembly includes an elongated handle member, said first handle
assembly handle member having an extended, upper portion, a medial,
pivot portion, and a lower portion, said first handle assembly
medial portion having a longitudinal axis; said first handle
assembly upper end includes a hand ledge, said hand ledge extending
generally perpendicular to the longitudinal axis of said first
handle assembly handle member upper portion and toward said central
longitudinal axis and wherein said hand ledge does not extend
beyond said central longitudinal axis when said first handle
assembly is in said first position; said second handle assembly
includes an elongated handle member, said second handle assembly
handle member having an extended, upper portion, a medial, pivot
portion, and a lower portion, said second handle assembly medial
portion having a longitudinal axis; and said second handle assembly
upper end includes a hand ledge, said hand ledge extending
generally perpendicular to the longitudinal axis of said second
handle assembly handle member upper portion and toward said central
longitudinal axis and wherein said hand ledge does not extend
beyond said central longitudinal axis when said second handle
assembly is in said first position.
20. The post hole digger of claim 19 wherein: when said first
handle assembly is in said first position, said first handle
assembly hand ledge extends to said central longitudinal axis; when
second first handle assembly is in said first position, said second
handle assembly hand ledge extends to said central longitudinal
axis; and wherein, when said first handle assembly and said second
handle assembly are in said first position, said first handle
assembly hand ledge abuts said second handle assembly hand ledge.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a post hole digger and, more
specifically, to a post hole digger having a traverse pivot point
coupling two handle assemblies to each other, a blade assembly
having two blade members, each blade member pivotally coupled to
one handle assembly, and an offset pivot point coupling the two
blade members to each other.
[0003] 2. Background Information
[0004] A post hole digger is structured to dig a hole having a
generally narrow cross-sectional area relative to the depth of the
hole. The hole was typically dug in a compacted particulate or
granulated material, hereinafter "the ground." The material removed
from the hole shall be referred to as "the dirt." The dirt was,
typically, a loose granulate material. Preferably, the post hole
had a greater cross-sectional area that a post that was inserted
therein. A portion of the loose dirt, or another material such as
concrete, was then reinserted into the annulus, or gap, between the
post and the ground. Because the compacted ground was more firm
than the loose dirt, and therefore provided better support for the
post, it was desirable to have as narrow of a hole as possible.
Thus, one factor in the design of a post hole digger was the span
of the post hole digger during insertion and, especially, during
removal. Keeping in mind that a worker must cyclically operate a
manual post hole digger, other important factors related to how a
worker interacted with the tool. Such factors included, but were
not limited to, the weight of the post hole digger, the force
required to operate the post hole digger, the amount of dirt
collected during each cycle, and the range of motion through which
a worker must act during each cycle. For example, a post hole
digger with longer handles typically had a longer lever arm and,
therefore, provided a greater closing force on the blade members.
However, the handles may not be too long as the tool could be too
heavy to lift repeatedly and/or too unwieldy to use
comfortably.
[0005] Manual post hole diggers generally had two elongated handles
with each handle having an upper hand grip portion and a blade
coupled to a lower end. The handles or blades were pivotally
coupled to each at a single pivot point. The blades moved between a
first, open position and a second, closed position that
corresponded to a first and second handle position. When the blades
were in the first, open position a user thrust the post hole digger
toward the ground and caused the blades to bite into the ground. To
maximize the force of the bite, the blades were generally
perpendicular to the ground when they were in the first, open
position. To further maximize the force of the bite, the handles
were generally vertically aligned with the blades so that
substantially all of the worker's effort (force) was directed
directly through the blades and into the ground. This configuration
further allowed the worker to position his/her hands and wrists in
a comfortable position, generally parallel to the ground. After the
blades engaged the ground, the worker moved the handles into the
second position thereby causing the blades to move into the second,
closed position. During this motion, the dirt is separated from the
ground. The closing force acting on the blades is related to the
force applied to the handles. The force applied to the handles was
enhanced by the length of the lever arm created by the length of
the handle. After the blades have been closed, the worker, while
holding the blades in the second, closed position, lifts the post
hole digger thereby removing the dirt from the hole.
[0006] The quantity of dirt held by the blades is controlled by the
shape of the blades and the nature of the dirt. Typically, the
blades are elongated and have an arcuate cross-sectional shape. The
blades were commonly somewhat pointed and the edges were shaped so
that, when the blades were in the second, closed position, the
blades substantially enclosed a quantity of dirt. The shape of the
blades was also related to the configuration of the pivot point and
the handles. That is, for example, if the blades were spaced far
apart, e.g. to engage a greater quantity of dirt, the handles would
have to travel through a greater arc in order to close the blades.
A greater arc requires a wider hole and more effort by the worker.
Lengthening the blades would reduce the amount of travel required
to close the blades, but would, in turn, reduce the relative lever
arm between the blades and the handles, thus requiring a greater
effort on the part of the worker.
[0007] In addition to the shape of the blades, the ease of use and
usability of a post hole digger was controlled by various factors
such as, but not limited to, the length and shape of the handles
and the type of the pivot point. As shown in FIG. 1, the most
typical configuration for a prior art post hole digger had handles
1, 2 about five to six feet in length, blade members 3, 4 about one
half foot to a foot in length, and an offset pivot point 5. That
is, each handle 1, 2 or blade 3, 4 had a tab 6, 7 extending toward
the other handle 1, 2 or blade 3, 4 with a pivot point 5 disposed
thereon. The pivot point 5, typically, had a pair of openings (not
shown), one on each tab 6, 7 and a pivot pin 8. The pivot point 5
was, typically, located near the interface between the handle 1, 2
and the associated blade 3, 4. Additionally, each tab had a length
of about three inches thereby providing a separation between the
handles, when in the first position, of about six inches. The
longitudinal axis of each handle 1, 2 is generally aligned with the
longitudinal axis for the associated blade 3, 4. Each handle 1, 2
further had a hand grip portion 9 disposed near the top of each
handle 1, 2. When coupled by an offset pivot point, the hand grip
portion 9 of each handle 1, 2 was located on the same side of the
pivot point 5 as the blade 3, 4, associated with that handle 1, 2.
To close the blades 3, 4 the worker pulled the handles 1, 2, apart.
To open the blades 3, 4 a worker moved the handles 1, 2 together
until the handles 1, 2 were generally parallel to each other.
Additionally, the handles 1, 2 or blades 3, 4, typically, had a
pivot stop structured to halt the rotation of the handles 1, 2 and
blades 3, 4 when the handles 1, 2 and blades 3, 4 were generally
parallel. With the blades 3, 4 held in a generally parallel
configuration, a worker could concentrate on the downward motion of
the tool without having to position the blades 3, 4 for the
bite.
[0008] An offset pivot post hole digger according to this
configuration is easy to manufacture and is not too heavy; however,
the range of motion of the handles is not suitable for a moderately
deep hole. When the handles 1, 2 are in the second position, i.e.
pulled apart, the span (width) of the tool increases as a function
of the distance from the pivot point 5. As the pivot point 5 is
disposed at the lower end of the handles 1, 2, essentially the
entire length of one handle 1 moves away from the other handle 2.
Thus, in order for the handles 1, 2 to be in the second position,
the hole must be wide. Conversely, when the handles are in the
first position, i.e., generally parallel, the tool is in its most
narrow configuration and can be easily inserted into the hole.
[0009] A post hole digger with a traverse pivot point has a
scissor-like configuration, as shown in FIG. 2, wherein pulling the
handles 1A, 2A apart results in the blades 3A, 4A moving apart and,
conversely, moving the handles 1A, 2A together results in the
blades 3A, 4A moving together. When a traverse pivot point 5A is
used, the pivot point 5A is typically located near the lower end of
the handles 1A, 2A, but above the blades 3A, 4A. As shown in FIG.
2, the blades 3A, 4A are generally disposed at an angle relative to
the longitudinal axis of the handles 1A, 2A so that that blades 3A,
4A may be positioned generally perpendicular to the ground while
still being separated. That is, if the blades 3A, 4A were generally
aligned with the associated handles 1A, 2A and the blades 3A, 4A
were in an open position, the blades 3A, 4A would not be generally
perpendicular to the ground. In this configuration, the post hole
digger is generally wider when the handles 1A, 2A are in the first
position and more narrow when the handles 1A, 2A are in the second
position. However, because the pivot point is located at a medial
position on the handles 1A, 2A, the range of motion is generally
smaller than on an offset pivot post hole digger.
[0010] It this configuration, a worker uses the, typically
stronger, pectoral muscles to push the handles 1A, 2A together to
close the blades 3A, 4A. While this could be considered an
advantage, this motion is also the opposite of the motion generally
associated with a post hole digger. As such, some workers do not
care for a traverse pivot point post hole digger. This
configuration also has a disadvantage in that, when thrusting the
tool downwardly, the worker must hold the handles 1A, 2A within a
generally narrow range of separation in order for the blades 3A, 4A
to be maintained generally perpendicular to the ground during the
bite. Moreover, the worker's hands may be in an awkward position
during the thrust. That is, on a traverse pivot point post hole
digger, the worker's hands are generally at an angle relative to
the ground on the down stroke.
[0011] There is, therefore, a need for a post hole digger with a
limited rage of motion between the handle first position and handle
second position.
[0012] There is a further need for a post hole digger having a
traverse pivot point that is also structured to maintain the
handles in a generally vertical and parallel orientation while the
blades are in the first, open position.
SUMMARY OF THE INVENTION
[0013] These needs, and others, are met by at least one embodiment
of this invention which provides a post hole digger having a first,
traverse pivot point, located on the medial portions of two handle
members, and a second, blade assembly pivot point located at the
medial point of the blade assemblies. Because the first pivot point
is a traverse pivot point, the handles are only required to travel
through a limited range of motion. Additionally, the second blade
assembly pivot point is preferably an offset pivot point. Thus,
because the second, blade assembly pivot point is disposed at a
medial point of the blade assemblies, the motion of the handle
members, which are coupled to the upper ends of the blade
assemblies, is reversed relative to the lower ends of the blade
members. In this configuration, the handle member's first position,
which corresponds to the blade assembly open position, is in the
preferred generally vertical and parallel orientation. Further,
once the post hole digger has engaged the ground, a worker uses the
preferred pulling apart motion on the handles to move the blade
assembly into the second, closed position. Additionally, the post
hole digger may utilize a hand ledge disposed at the upper end of
each handle as a stop member. That is, each hand ledge extends
toward the opposite handle and is sized to abut the opposing hand
ledge when the handles are generally parallel to each other. Thus,
a worker does not have to manually maintain the position of the
handle members as with the prior art traverse pivot point post hole
diggers. As an added advantage, the hand ledges also help to resist
the workers hands slipping upwardly on the handles when the worker
lifts the post hole digger out of the hole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] A full understanding of the invention can be gained from the
following description of the preferred embodiments when read in
conjunction with the accompanying drawings in which:
[0015] FIG. 1 is a front view of a prior art offset pivot post hole
digger.
[0016] FIG. 2 is a front view of a prior art traverse post hole
digger.
[0017] FIG. 3 is a front view of a post hole digger in a first
position.
[0018] FIG. 4 is a front view of a post hole digger in a second
position.
[0019] FIG. 5 is a side view of a post hole digger.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] As used herein an "offset pivot point" shall mean a
configuration wherein each handle and associated blade may be, and
generally are, disposed on the same side of the pivot point, the
pivot point being located on one or more structures extending
toward the opposing handle/blade.
[0021] As used herein a "traverse pivot point" shall mean a
scissor-like configuration wherein two members cross over each
other with the pivot point extending through the point of
intersection.
[0022] As used herein, "coupled" means a link between two or more
elements, whether direct or indirect, so long as a link occurs.
[0023] As used herein, "directly coupled" means that two elements
are directly in contact with each other.
[0024] As used herein directional words, such as, but not limited
to, "upper" and "lower" shall be used in relation to the Figures
and are not limiting upon the claims.
[0025] As shown in FIGS. 3 and 4, a post hole digger 10 includes a
first handle assembly 20, a second handle assembly 20A, and a blade
assembly 40. The first handle assembly 20 and the second handle
assembly 20A are substantially similar in configuration except that
the second handle assembly 20A is a mirror image of the first
handle assembly 20. Accordingly, the following description will be
addressed to the elements of the first handle assembly 20 and it is
understood that the second handle assembly 20A includes
substantially similar element. Elements of the second handle
assembly 20A shall use like reference numbers as the elements of
the first handle assembly 20 and will be further identified with
the letter "A." For example, and as described below, the first
handle assembly 20 has a handle member 22. Thus, the second handle
assembly 20A has a handle member 22A.
[0026] The first handle assembly 20 includes an elongated handle
member 22 having an elongated, upper portion 24, a medial portion
26, and a lower portion 28. The first handle assembly handle member
upper portion 24 has an upper end 30. The first handle assembly
lower portion 28 has a lower end 32. The first handle assembly
upper portion 24 has a longitudinal axis 25. The first handle
assembly medial portion 26 has a longitudinal axis 27. The first
handle assembly lower portion 28 has a longitudinal axis 29. The
first handle assembly medial portion 26 has a pivot opening 34
extending generally perpendicular to the first handle assembly
medial portion longitudinal axis 27. The first handle assembly
lower end 32 has a first blade sub-assembly pivot opening 36
extending generally perpendicular to the first handle assembly
lower portion longitudinal axis 29.
[0027] As shown in FIG. 3, the angle, identified as angle "A,"
between the first handle assembly handle member upper portion
longitudinal axis 25 and the first handle assembly handle member
medial portion longitudinal axis 27 is between about 20 to 24
degrees, and more preferably about 22.5 degrees. The angle,
identified as angle "B," between the first handle assembly handle
member lower portion longitudinal axis 29 and the first handle
assembly handle member medial portion longitudinal axis 27 is
between about 26 to 30 degrees, and more preferably about 28
degrees. It is noted that the angle B is in a direction opposite
angle A. The first handle assembly upper portion 24 has a length
between about 29.0 and 37.0 inches, and more preferably about 33.0
inches. The first handle assembly medial portion 26 has a length
between about 6.5 and 8.5 inches, and more preferably about 7.5
inches. The first handle assembly lower portion 28 has a length
between about 3.0 and 7.0 inches, and more preferably about 5.0
inches.
[0028] The blade assembly 40 includes a first blade sub-assembly 50
and a second blade sub-assembly 50A. As with the first and second
handle assemblies 20, 20A, the first blade sub-assembly 50 and
second blade sub-assembly 50A are substantially similar and mirror
images of each other. As such, only the elements of the first blade
sub-assembly 50 will be described in detail below. It is understood
that that the second blade sub-assembly 50A includes substantially
similar elements. Elements of the second blade sub-assembly 50A
shall use the same reference numbers as the elements of the first
blade sub-assembly 50 and will be further identified with the
letter "A." For example, and as described below, the first blade
sub-assembly 50 has a blade portion 51. Thus, the second blade
sub-assembly 50A has a blade portion 51A.
[0029] As shown in FIGS. 3 and 4, the first blade sub-assembly 50
has a lower, blade portion 51 and an upper base portion 54. The
first blade sub-assembly blade portion 51 has a longitudinal axis
53 (FIG. 5). The first blade sub-assembly base portion 54 also has
a longitudinal axis 55. The first blade sub-assembly blade portion
51 has an elongated blade body 56 having an upper end 58 and a
lower end 60. The first blade sub-assembly blade portion 51 has a
length between about 9.5 and 11.5 inches, and more preferably about
10.5 inches. The first blade sub-assembly blade body 56 has a
generally arcuate cross-section extending about 180 degrees. The
first blade sub-assembly blade body lower end 60 is, preferably,
tapered to a point. The angle of the taper is governed by the
configuration of the post hole digger, but generally, the taper is
such that when the first blade sub-assembly 50 and the second blade
sub-assembly 50A are in the closed position, as described below,
the first blade sub-assembly blade body lower end 60 and the second
blade sub-assembly blade body lower end 60A substantially engage
each other so that the first blade sub-assembly 50 and the second
blade sub-assembly 50A form a cup-like structure. The first blade
sub-assembly blade portion 51 further includes at least one, and
preferably two, offset tabs 62 (one shown). The first blade
sub-assembly offset tabs 62 extend, generally perpendicular to the
first blade sub-assembly blade member longitudinal axis 53, from
the first blade sub-assembly blade portion upper end 58. The first
blade sub-assembly offset tabs 62 each have a length of between
about 4.5 and 5.5 inches, and more preferably about 5.0 inches.
Each first blade sub-assembly offset tab 62 has a distal opening 66
therein. The first blade sub-assembly offset tab openings 66 on
different offset tabs 62 are generally aligned with each other.
[0030] As shown on FIG. 4, the first blade sub-assembly base
portion 54 has an upper, first end 72. The first blade sub-assembly
blade base body upper first end 72 is also shaped with a generally
U-shaped cross-section, however, the first blade sub-assembly blade
base body upper first end 72 is much smaller than the associated
blade portion 51. The first blade sub-assembly blade base body
upper first end 72 forms a clevis 82 structured to accommodate the
first handle assembly lower end 32. The clevis 82 has aligned
openings 84 therein. The first blade sub-assembly blade portion 51
and the first blade sub-assembly base portion 54 may be angled
relative to each other, identified as angle .degree. C. in FIG. 3.
In a preferred embodiment, the first blade sub-assembly base
portion longitudinal axis 55 is angled between about 18 to 22
degrees, and more preferably about 20.3 degrees relative to the
first blade sub-assembly blade portion longitudinal axis 53.
[0031] The first blade sub-assembly 50 and the second blade
sub-assembly 50A are directly coupled to each other at a blade
assembly pivot point 90. The blade assembly pivot point 90 is
disposed at the interface between the first blade sub-assembly
offset tabs 62 and the second blade sub-assembly offset tabs 62A.
That is, when the first blade sub-assembly blade portion 51 and the
second blade sub-assembly blade portion 51A are positioned opposite
of and facing each other, the first blade sub-assembly offset tabs
62 and the second blade sub-assembly offset tabs 62A extend toward
and overlap each other so that the first blade sub-assembly offset
tab openings 66 generally align with the second blade sub-assembly
offset tab openings 66A. The blade assembly pivot point 90 is
created by separate pivot pins 92 extending through each set of
aligned offset tab openings 66 and 66A.
[0032] To resist creating torque about the central longitudinal
axis 100, described below, it is desirable to have the first and
second handle assembly handle member upper portions 24, 24A
disposed in the same general plane. As the first and second handle
assembly handle member medial portions 26, 26A are pivotally
coupled together, and therefore cannot be in the same plane, each
handle assembly handle member 22, 22A may include a lateral
transition section 94, 94A. That is, as shown in FIG. 5, the first
handle assembly handle member lower portion 28 and the first handle
assembly handle member medial portion 26 are generally disposed in
a first lower plane. Similarly, the second handle assembly handle
member lower portion 28A and the second handle assembly handle
member medial portion 26A are generally disposed in a second lower
plane. The first handle assembly handle member medial portion
lateral transition section 94 is disposed between the first pivot
point 14 (described below) and the first handle assembly handle
member upper portion 24.
[0033] The first handle assembly medial portion lateral transition
section 94 is offset from the first lower plane toward a centrally
disposed upper plane. Similarly, second handle assembly handle
member medial portion lateral transition section 94A is disposed
between the first pivot point 14 (described below) and the second
handle assembly handle member upper portion 24A. The second handle
assembly medial portion lateral transition section 94A is offset
from the first lower plane toward a centrally disposed upper plane.
Thus, when the first and second handle assemblies 20, 20A are
coupled at the first pivot point 14 as described below, the first
handle assembly handle member upper portion 24 and the second
handle assembly handle member upper portion 24A are disposed in
generally the same plane.
[0034] When the post hole digger 10 is assembled, the first handle
assembly handle member 22 is pivotally coupled to the second handle
assembly handle member 22A by a pivot pin 12 extending through the
first handle assembly medial portion pivot opening 34 as well as
the second handle assembly medial portion pivot opening 34A. The
first handle assembly handle member 22 and the second handle
assembly handle member 22A are oriented so as to generally be
mirror images of each other. In this configuration, the first
handle assembly handle member 22 and the second handle assembly
handle member 22A cross over each other at the location of the
first and second handle assembly medial portion pivot opening 34,
34A. Thus, this pivot point is a traverse, first pivot point
14.
[0035] The blade assembly 40 is pivotally coupled to the first and
second handle assemblies 20, 20A. More specifically, the first
blade sub-assembly 50 is pivotally coupled to the first handle
assembly handle member lower end 32 by a first blade sub-assembly
pivot-pin 49. The first blade sub-assembly pivot pin 49 extends
through the first blade sub-assembly clevis 82 as well as the first
handle member first blade sub-assembly pivot opening 36. Similarly,
the second blade sub-assembly 50A is pivotally coupled to the
second handle assembly handle member lower end 32A by a second
blade sub-assembly pivot pin 49A. The second blade sub-assembly
pivot pin 49A extends through the second blade sub-assembly clevis
82A as well as the second handle member second blade sub-assembly
pivot opening 36A. The first handle assembly lower end 32 is
between about 6 and 10 inches, and preferably 8.0 inches, from the
traverse, first pivot point 14. In this configuration, the tool
assembly has a central longitudinal axis 100 extending through the
traverse, first pivot point 14 and the blade assembly pivot point
90. It is further noted that, because each blade sub-assembly 50,
50A remains substantially to one side of the blade assembly pivot
point 90, the blade assembly pivot point 90 is an offset pivot
point.
[0036] In this configuration the first handle assembly 20 and the
second handle assembly 20A are structured to pivot relative to each
other between a first position, wherein the first handle assembly
upper end 30 and the second handle assembly upper end 30A are
generally adjacent to each other and a second position wherein the
first handle assembly upper end 30 and the second handle assembly
upper end 30A are generally are generally spaced from each other.
As the first handle assembly 20 and the second handle assembly 20A
move between the first and second positions, the first blade
sub-assembly 50 and the second blade sub-assembly 50A move between
a corresponding first, open position and a second, closed position.
That is, the first blade sub-assembly 50 and the second blade
sub-assembly 50A are structured to pivot relative to each other
between a first, open position and a second, closed position
wherein when the first handle assembly 20 and the second handle
assembly 20A are in the first position, the first blade
sub-assembly 50 and the second blade sub-assembly 50A are in the
first, open position, and, when the first handle assembly 20 and
the second handle assembly 20A are in the second position, the
first blade sub-assembly 50 and the second blade sub-assembly 50A
are in the second, closed position.
[0037] Because the first pivot point 14 is a traverse pivot point,
as the first handle assembly upper end 30 and the second handle
assembly upper end 30A move apart, the first handle assembly lower
end 32 and the second handle assembly lower end 32A also move
apart. As the first handle assembly lower end 32 and the second
handle assembly lower end 32A move apart, the first blade
sub-assembly clevis 82, which is coupled to the first handle
assembly lower end 32, and the second blade sub-assembly clevis
82A, which is coupled to the second handle assembly lower end 32A,
also move apart. Because the blade assembly pivot point 90 is an
offset pivot point, as the first and second blade sub-assembly
blade base body upper, first ends 72, 72A move apart, the first and
second blade sub-assembly blade body lower ends 60, 60A move toward
each other.
[0038] Preferably, the traverse, first pivot point 14 and the blade
assembly pivot point 90 are disposed between 9.0 and 15.0 inches
apart, and more preferably about 12.0 inches apart. Thus, as shown
on FIG. 4 by angle "D," the range of motion for the first and
second handle assemblies 20, 20A moving between the first and
second positions is between about 6.5 degrees and 10.5 degrees
relative to the central longitudinal axis 100, and more preferably
about 8.5 degrees. Additionally, as represented by the angle "E,"
the first and second blade sub-assembly blade portions 51, 51A
travels between about 12 and 18 degrees, and more preferably about
15 degrees relative to the central longitudinal axis 100 as the
first blade sub-assembly 50 moves between the first, open position
and the second, closed position.
[0039] The handle assemblies 20, 20A may also include cooperative
stop members 110, 112 structured to arrest the movement of the
handle first and second members 22, 22A toward each other. In one
embodiment, the cooperative stop members 110, 112 are hand ledges
120, 120A. One hand ledge 120, 120A is disposed at each handle
assembly upper end 30, 30A. Thus, a first hand ledge 120 extends
generally perpendicular to the longitudinal axis of the first
handle assembly handle member upper portion 24 and toward the
central longitudinal axis 100. Similarly, a second hand ledge 120A
extends generally perpendicular to the longitudinal axis of the
second handle assembly handle member upper portion 24A and toward
the central longitudinal axis 100. The hand ledges 120, 120A do not
extend beyond the central longitudinal axis 100 when the first and
second handle assemblies 20, 20A are in the first position and,
more preferably, the hand ledges 120, 120A abut each other when the
first and second handle assemblies 20, 20A are in the first
position.
[0040] Alternatively, a pair of cooperative stop members 110, 112
may be disposed, one each, along the middle of the first handle
assembly upper portion 24 and the middle of the second handle
assembly upper portion 24A. The cooperative stop members 110, 112
include a tab 130, 130A that extends generally perpendicular to the
longitudinal axis of the associated handle assembly handle member
upper portion 24, 24A and toward the central longitudinal axis 100.
The tabs 130, 130A abut each other when the first and second handle
assemblies 20, 20A are in the first position.
[0041] While specific embodiments of the invention have been
described in detail, it will be appreciated by those skilled in the
art that various modifications and alternatives to those details
could be developed in light of the overall teachings of the
disclosure. Accordingly, the particular arrangements disclosed are
meant to be illustrative only and not limiting as to the scope of
invention which is to be given the full breadth of the claims
appended and any and all equivalents thereof.
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